Interengageable structural members

ABSTRACT

Structural members (80) having an intermediate web (81) and hollow tubular side flanges (83, 85) extending longitudinally of the web (81) are formed in a cold rolling operation such that one of the tubular side flanges (83) has an outside diameter of the opposite tubular side flange (85). The larger diameter side flange (85) has a longitudinally slotted aperture (87) to permit a composite structure (120) to be formed by nesting the smaller diameter flange (83) in the larger diameter flange (85) of an adjacent structural member (80). The composite structure (120) having a plurality of interconnected structural members (80) may be assembled as a closed or open structure.

This invention is concerned with novel structural members and a processfor manufacturing same.

International patent application Ser. No. PCT/AU89/00313 describes amethod for formation of structural members wherein a single strip ofmetal is continuously cold roll-formed to provide a central web with ahollow flange extending along each longitudinal edge. Although thecentral web is usually planar it may be contoured in a transversedirection. The hollow flanges may be formed in any suitable crosssectional shape such as circular, rectangular, triangular or the likeand they may be of the same or different sizes.

In a further Australian patent application Ser. No. (PCT/AU91/00442)there is described a substantial improvement in the method and structureof the structural members disclosed in earlier International patentapplication Ser. No. PCT/AU89/00313. This further application describesthe formation of structural members comprising at least one web havingat least one hollow flange extending along a longitudinal edge thereof.

The improvement described in the further application relates to thecontinuous fabrication in cold roll forming machines of structuralmembers formed from a multiplicity of separate metal strips. Thisimproved process enables the manufacture of structural members having aweb (or webs) and a hollow flange (or flanges) wherein the web andflange components may be comprised of differing metal thicknesses andgrades depending upon the requirement of the structural member. Inaddition, the improved process enables structural members to be formedin a wide variety of configurations.

The present invention relates to new and improved structural members andnovel uses therefor, the new and improved structural members beingfabricated generally in accordance with the processes of theabovementioned applications. Accordingly, the disclosures of patentapplications PCT/AU89/00313 and PCT/AU91/00442 are incorporated hereinby way of cross reference and references herein to "roll forming" as itrelates to the invention, the subject of this patent application mean"cold rolling forming".

According to one aspect of the present invention there is provided astructural member comprising:

a first hollow flange and a second flange extending longitudinally of anintermediate web, said first flange including a slotted apertureextending longitudinally thereof in a direction parallel to alongitudinal axis of said first flange.

The second flange may comprise a solid element although preferably thesecond flange is hollow. If required said first and second flange may behollow and both of said first and second flanges may include a slottedaperture extending longitudinally thereof.

Suitably said first flange is adapted to receivably locate within itsinterior a flange of an adjacent structural member comprising at leastone web element and at least one flange element extending longitudinallyof an edge of said web element, said web element extending through saidslotted aperture when said at least one flange element is receivablylocated within the interior of said first flange.

Suitably, the second flange has a cross sectional area less than thecross sectional area of the interior of the first hollow flange.

The first and second hollow flanges may have the same or different crosssectional shapes.

Preferably the cross sectional shapes of said first and second flangesare similar or identical.

Most preferably first flange may be adapted in use to receivably locatea second flange of an adjacent substantially identical structuralmember.

The intermediate web member may be substantially planar or alternativelyit may be contoured transversely of a longitudinal axis of saidstructural member.

If required, the web and the first and second flanges may comprise thesame grade and thickness of metal or differing grades and thickness ofmetal.

Suitably the slotting aperture may be in the same plane as theintermediate web or in another plane inclined thereto.

The slotted aperture may be of a width such as to substantially restrainrelative rotational motion about a longitudinal axis between said firstflange and a flange receivably located therein or alternatively thewidth of said slotted aperture may be such as to permit at least limitedrotational motion between said first flange and a flange receivablylocated therein.

According to a second aspect of the invention there is provided acomposite structure comprising:

two or more structural members having an intermediate flange and aspaced parallel side flanges, at least one of said side flangescomprising a hollow flange having a slotted aperture extendinglongitudinally thereof, said hollow flange receivably locating a sideflange of an adjacent structural member.

Suitably at least one of said structural members includes a slottedhollow side flange adopted to receive two or more side flanges ofadjacent structural members.

The composite structure may comprise a plurality of structural memberseach interconnecting with an adjacent structural member to form asubstantially planar or non planar open composite structure.

Alternatively the composite structure may comprise a plurality ofstructural members each interconnecting with one or more adjacentstructural members to form a single closed composite structure or acomposite structure comprising open and closed portions.

The composite structure may comprise a rigid structure wherein relativemovement between adjacent structural members is restrained by limitingrelative rotation between a hollow flange having a slotted aperture anda flange of an adjacent structural member receivably located therein.

Alternatively the composite structure may comprise a flexible structurewherein at least limited rotational movement between adjacent structuralmembers is permitted.

According to yet another aspect of the invention there is provided amethod of manufacture for a structural member comprising the steps of:

fabricating a structural member having an intermediate web and sideflanges extending longitudinally of said web, at least one of said sideflanges comprising a hollow aperture extending longitudinally thereof,and;

forming a slotted aperture longitudinally of a wall of said at least oneside flange.

The structural member may be formed by any suitable fabrication processbut preferably is formed in a cold roll forming operation from a singlestrip of metal or from a plurality of strips of metal.

The slotted aperture may be formed by any suitable process of metalremoval. For example the metal in the region of the slotted aperture maybe removed by abrasion with a grinding wheel or a strip of metal may beremoved by cutting wheels, shears or the like. Alternatively a strip ofmetal may be removed by a gas plasma metal cutting apparatus or a lasercutting apparatus.

The slotted aperture may also be formed by a roll forming processwherein the hollow flange is formed from a strip of metal leaving thefree edges of the strip separated. Alternatively the slotted aperturemay be formed by a roll forming process wherein a hollow tubular memberis initially formed followed by an inward deformation of the tubularmember to form a double walled hollow flange with a slotted apertureextending longitudinally thereof.

In order that the various aspects of the invention may be more fullyunderstood, preferred embodiments will now be described with referenceto the accompanying drawings in which FIG. 1 shows schematically thedevelopment of cross sectional shape in a roll formed structural memberformed from a single strip of metal.

FIGS. 2-4 show typical work station roller profiles to develop the crosssectional shapes illustrated in FIG. 1.

FIG. 5 shows schematically the welding of the free edges of the hollowflanges of the section illustrated in FIGS. 1-4.

FIG. 6a through h show schematically cross sections during the rollforming of a hollow flanged structural member fabricated from separatestrips of metal.

FIG. 7 shows schematically a roll forming apparatus to produce the rollformed section of FIG. 6.

FIGS. 8-15 show schematically typical profiling stations in the rollforming apparatus of FIG. 7.

FIGS. 16-18 show alternative forms of attachment of hollow flanges toweb sections.

FIGS. 19a and b through FIGS. 23a and b illustrate a non-exhaustivearray of alternative cross sectional profiles of structural members.

FIG. 24 shows schematically a composite beam structure.

FIG. 25 shows a cross sectional profile of a structural member accordingto the present invention.

FIG. 26 shows a further cross sectional profile of a structural memberaccording to the present invention.

FIG. 27 shows another cross sectional profile according to theinvention.

FIG. 28 shows yet another cross sectional profile.

FIGS. 29 and 30 show enlarged cross sectional views of interengaginghollow flanges.

FIG. 31 shows a non-exhaustive array of composite structures accordingto the invention.

FIGS. 32 and 33 show schematically alternative methods for forminghollow flanged structural members.

FIG. 34 shows a composite structure according to yet a further aspect ofthe invention.

FIG. 35 shows schematically a further method for forming a structuralmember with one or more slotted hollow flanges.

FIG. 1 shows schematically a typical development of a cross sectionalprofile from a single strip of metal according to the process describedin application Ser. No. PCT/AU88/00313.

As shown in greater detail in FIGS. 2-4 a planar strip of metal isprogressively deformed to produce a cross sectionally arcuateintermediate web 1 with hollow flanges 2 having a generally circularcross-section extending longitudinally of web 1. Although deforming andshaping roller sets 3, 4 and 5 as shown co-operate to produce hollowflanges 2 of identical cross-sectional diameter, it will be clear to askilled addressee that with appropriate modification, roller sets 3,4and 5 may be adapted to produce hollow flanges 2 of differing crosssectional diameters and/or shape.

FIG. 5 shows schematically the continuous welding of the free edges ofhollow flanges 2 to the central web 1 to form a structural member havingimmense structural integrity and fluid tight hollow flanges 2.

Welding of the free edges of flanges 2 is suitably effected by a highfrequency electrical induction or resistance welding apparatus showngenerally at 7. After welding, the central web 2 may be reshaped byfurther deforming or shaping rollers (not shown) to produce a web 2having a planar or profiled cross sectional shape.

FIG. 6 shows schematically the development of a structural member fromseparate strips of metal according to a process and apparatus describedin Australian patent application Ser. No. PCT/AU91/00442.

At stage 1, metal strips representing web strip 10 and flange strips 11,12 are fed into a tandem station roll forming apparatus or alternativelyflange strips 11, 12 are passed through separate roll forming millswhile web strip 10 passes therebetween.

Strips 11, 12 are progressively deformed to produce hollow side flanges13, 14 having elongate slotted apertures 13a, 14a respectively as shownat stage 4. The hollow flanges 13, 14 are guided towards web strip 10until the free edges of web strip 10 are located within slottedapertures 13a, 14a. The free edges of flanges 13, 14 are then urged intocontact with web strip 10 as shown at stage 5 by opposing rollers in theregion of a welding station wherein the free edges of flanges 13, 14 arewelded to web strip 10 to form an integral structure.

Flanges 13, 14 may then be shaped to any desired shape as illustrated atstages 6-8 by shaping rollers located downstream of the welding station.

FIG. 7 shows schematically an apparatus used to produce the structuralmember of FIG. 1.

In FIG. 7 the apparatus comprises separate let-off stations 30, 31, 32each supporting separate coiled rolls 33, 34, 35 of sheet steel, each ofthe same or different thickness and width if required. Strips 36 and 38issuing from rolls 33, 35 respectively are directed to roll formingmills 39,40 to form hollow members 41, 42 respectively of predeterminedshape and cross sectional area. As illustrated at stage 4 in FIG. 6, therespective pairs of free edges are slightly separated to form continuousslots which face a respective edge of central strip or web 37.

In the region of welding station 43 the free edges of web 37 are guidedby rollers 44 into the respective slots in adjacent hollow members 41,42 to a respective distance equal to the respective wall thicknesses ofmembers 41, 42. Nip rollers 45 compress members 41,42 to urge theirrespective free edges into contact with upper and lower surfaces of web37 immediately prior to welding by high frequency electrical inductionor resistance welding units 46. Rollers 47, 48, 49 and 50 initiallysupport web 37 and subsequently the integral structure 51.

The structure 51 is then severed into predetermined lengths by a flyingsaw (not shown) or the like.

Suitably roll forming mills 39, 40 are laterally movable to accommodatediffering widths of web 37.

FIGS. 8-15 show schematically typical rolling stations which may beemployed in rolling mills 39, 40 in FIG. 7 to produce the hollow flangemembers 13, 14 shown at stage 4 in FIG. 6.

A number of significant variations may be made to the method andapparatus of the invention to achieve a wide variety of structuralmembers.

FIG. 16 shows, for example, that the system of FIG. 7 may be adaptedsuch that in the process of welding the lips 60 of a slotted tubularmember to the opposing surfaces of a web member 63, a free edge 61 ofthe web member may be guided fully into either or both of the tubularmembers 62 until it engages the inner wall of the tubular member. Ifrequired the free edge of the web 63 may be additionally welded to theinterior of the tubular member 62 by high frequency induction welding toform a hollow flange divided into separate fluid tight compartments.

FIG. 17 shows an alternative configuration wherein lips 60 are welded toopposing faces of web 63 adjacent its edges.

FIG. 18 shows yet another configuration wherein a free edge 64 of web 63is welded to the outer surface of a hollow flange 65 having a slottedaperture 66 extending longitudinally thereof diametrically opposite theattachment point of web 63. Slotted aperture 66 is formed by leaving thefree edges 65a of flange 65 separated and maintaining the separation ata predetermined spacing during the shaping process by projections 67 onouter rolls 68.

In other variations the central web may include pre or post formedapertures or it may include a longitudinally or transversely extendingprofiled shape in the form of deep or shallow channels, ribs or thelike. In the case of transversely extending contoured profiles, theinwardly facing regions of opposed hollow flanges include planar facesarranged perpendicularly to the edges of the web to facilitate weldingof the components of the structural member.

FIGS. 19a and b through FIGS. 23a and b show a non-exhaustive array offlange shapes comprising an intermediate web 10 and opposed hollowflanges 13, 14 according to the invention disclosed in Australianapplication Ser. No. PK2531.

FIG. 24 in particular shows a composite structure formed in accordancewith the inventions disclosed in both Australian application Ser. No.PCT/AU88/00313 and Ser. No. PCT/AU91/00442. In this structure the lowerportion comprising flanges 70, 71 and web 72 is formed from a singlestrip of metal in accordance with application PCT/AU88/00313 to which issubsequently added web 73 and hollow flange 74 (formed from separatestrips of metal) in accordance with the invention described inAustralian application Ser. No. PK2531.

Reference to FIGS. 1-24 and the disclosures of patent application Ser.Nos. PCT/AU88/00313 and PCT/AU91/00442 is for the purpose of a clearerunderstanding of the present invention and it should be understood thatthe disclosures of these applications are incorporated herein by way ofcross reference and the configurations, shapes and fabrication processesof structural members are applicable to adaptation in accordance withthe present invention.

FIG. 25 shows a cross-sectional configuration of a structural member 80formed in accordance with the present invention. The structural member80 comprises a web 81 having an arcuate stiffening rib 82 formedtherein. A hollow flange 83 has its free edge 84 welded to web 81 toform a fluid impervious conduit.

A second hollow flange 85 is formed on the opposite side of web 81 andthe free edge 86 of flange 85 is also welded to web 81. A slottedaperture 87 is formed in the wall of flange 85 in the same plane as web21.

The outer diameter of flange 83 is slightly smaller than the innerdiameter of flange 85 whereby adjacent structural members 80 may beinterconnected to form a composite structure by lengthwise slidinglyengaging small flange 83 of one structural member within a large flange85 of another structural member.

The structural member 80 may be formed from one or more strips of metalas generally described above and the slotted aperture is formed afterthe free edge 86 of flange 85 is welded to web 81. The slotted apertureis formed continuously by a gas plasma or laser cutting apparatus andthe strip of metal removed is discarded as scrap.

FIG. 26 shows an alternative configuration of a structural member 90wherein web 91 is formed as a channel-like section. Flange 92 is of asmaller diameter than flange 93 whereby after slotting flange 93, flange92 may be slidingly located therein.

FIG. 27 shows a similar configuration to FIG. 26 except that a muchthicker strip of metal is employed to fabricate the structural member90.

FIG. 28 shows yet another embodiment of a structural member 97comprising a channel shaped web 95 and a pair of hollow flanges 96 ofequal diameter having large slotted apertures 98, 99, the purpose ofwhich will be described with reference to FIGS. 29 and 30.

FIG. 29 is an enlarged cross sectional view of a small flange 92 of thestructural member 90 shown in FIG. 27 engaged in a slotted aperture 100of flange 93 of an adjacent structural member 90. Slotted aperture 100is of a width greater than the thickness of web 91 to allow it limitedpivotal movement between flanges 92 and 93.

FIG. 30 shows an enlarged cross sectional view of the interengagingflanges 92 and 93 of FIG. 29 engaged within a slotted flange 96 ofstructural member 97 shown in FIG. 28. Relative pivotal movement betweenflanges 92, 93 and 96 is permitted to at least a limited degree.

FIG. 31 illustrates composite structures permissable with the structuralmembers illustrated generally in FIGS. 27, 28 and 29.

FIGS. 31a, 31b and 31c show cross sections of hollow columnar structureswhich may be utilized as structural columns, free standing poles or boxbeams. These structures may be hollow or filled with reinforced concrete(with or without pre-stressing steel reinforcing bars) or otherreinforcing material such as carbon, synthetic or glass fibres in aresin matrix. If required, the columnar structures may also includepost-stressed tendons.

FIG. 31d shows a composite structure comprising interconnectedstructural members shown generally in FIGS. 26 and 27. This compositestructure may be utilized in an upright manner as a structural barriersuch as a wall for a building, marine piling, shuttering for earthworksor the like.

In a horizontal configuration, the interconnected structural members mayform a reinforced support for concrete slab floors, mine wall and roofreinforcing barriers or even as horizontal walling on a structuralframe.

FIG. 31e shows yet another structural configuration comprising acombination of structural members illustrated in FIGS. 26, 27 and 28wherein the structural members of FIG. 28 form spaced columns or boxbeams 101 to provide additional upright or transverse reinforcing to abarrier-like structure.

A structural member 102 interconnected to a junction 103 of adjacentinterconnecting structural members 104 and arranged perpendicularlythereto may form an alternative form of structural support orreinforcing to a composite structure according to the invention.

FIG. 32 shows an alternative method of fabricating structural elementsaccording to the invention.

The structural member 110 is fabricated by continuously forge weldingflange strips 111, 112 to a web 113. Forge welding is a well knownprocess for fabricating I- and T- beams and is generally described inU.S. Pat. No. 3,713,205.

Downstream of the forge welding station is a roll forming mill whichdeforms flange strips 111, 112 away from web 113 to form hollow flanges114, 115. Hollow flange 114 is formed as a closed integral member byfusing together the free edges of flange strip 111 by high frequencyelectrical induction or resistance welding. Hollow flange 115 may beformed in a similar manner by fusing together the free ends of flangestrip 112 and then subsequently forming slotted aperture 116 by removinga strip of metal by, say, a gas plasma or laser metal cutting apparatus.

Alternatively, slotted aperture 116 may be formed by roll forming flangestrip 112 such that its free edges are spaced to form aperture 116.

FIG. 33 shows a variation of the process described in FIG. 32.

In this variation flange strip 111 is deformed towards web 113 and thefree ends of flange strip 111 are fused to the sides of web 113 to forma hollow flange 114 which is internally reinforced by the edge portionof web 113.

The free ends of flange strip 111 are fused to web 113 by high frequencyelectrical induction or resistance welding.

FIG. 34 shows a composite structure comprising a plurality of structuralmembers 120 each comprising a web 121 with a closed hollow flange 122extending along one side of web 121 and a larger hollow flange 123extending along the opposite side of web 121.

Hollow flange 123 includes a slotted aperture 124 extendinglongitudinally thereof and parallel to the plane of web 121. Theinternal diameter of flange 123 is chosen to accommodate an oppositesmaller hollow flange of an adjacent structural member.

The composite structure so formed provides a sheet-like structurereinforced by hollow flanges 122 and 123. The width of slotted aperture124 may be chosen to permit a relatively rigid composite structure or atleast limited co-axial relative rotation between engaging flanges 123,124 to permit an arcuate or contoured structure rather than the planarstructure illustrated.

Such a composite structure may be employed as a structuralsupport/lining for tunnels, bridge construction etc. In thin gaugemetal, such a structure may be employed as roofing or wall cladding. Inheavier gauges, the structure may be employed as piling or shuttering inearthworks.

In FIG. 35 a structural member 130 having a hollow flange 131 may beformed from a single metal strip by a process described in applicationSer. No. PCT/AU90/00313 or from a plurality of metal strips by a processdescribed in patent application Ser. No. PK2531.

The hollow flange 131 is when deformed in a continuous roll formingoperation to flatten the flange to form a double walled planar flange132 extending longitudinally of an edge of web 133.

Planar flange 132 is subsequently deformed by roll forming to produce agenerally hollow double walled flange 134 with a longitudinal slot 135extending therealong. While hollow slotted flange 133 is shown asgenerally circular in cross section it should be appreciated that thecross-sectional shape may be roll formed to any suitable cross section.

This variation of the process according to the invention may be employedto provide a reinforced hollow flange where the use of a thicker flangestrip may not be possible or otherwise where the use of a thin flangestrip is advisable for economic or process efficiency reasons.

It will be readily apparent to a skilled addressee that manymodifications or variations may be made in the products and processesaccording to the invention without departing from the spirit and scopethereof.

I claim:
 1. A method for the manufacture of structural members adaptedfor telescopic edge to edge engagement with a like structural member,said method comprising the steps of:cold roll forming a structuralmember having an intermediate web member and opposed closed hollow sideflanges extending along opposite sides of said web, said hollow sideflanges being closed by welding the free edges thereof to respectivejunctions between the intermediate web and the hollow flanges; andforming a slotted aperture in at least one of said hollow side flanges,said slotted aperture extending between opposed ends of said hollow sideflange parallel to said intermediate web.
 2. A method as claimed inclaim 1 wherein said structural member is formed in a continuous rollforming process from a single strip of material and the opposed freeedges of the strip are welded by high frequency electrical induction orresistance welding to the surface of the strip at the junction betweenthe hollow flange and the intermediate web.
 3. A method as claimed inclaim 2 wherein the slotted aperture is formed by removal of materialfrom a closed wall of said hollow flange.
 4. A method as claimed inclaim 1 wherein the structural member is formed in a continuous rollforming process from separate strips of material comprising saidintermediate web and at least one of said hollow flanges, wherein freeedges of the strip comprising said at least one hollow flange are fusedon opposite surfaces of said web adjacent an edge thereof by highfrequency electrical induction or resistance welding.
 5. A method asclaimed in claim 4 wherein said slotted aperture is formed by removal ofmaterial from a closed wall of a hollow flange.
 6. A method as claimedin claim 1 wherein said slotted aperture is formed by initially forminga hollow tubular flange which is subsequently deformed inwardly to forma double walled hollow flange with a slotted aperture extending betweenthe ends thereof.
 7. The method as claimed in claim 1 and wherein saidslotted aperture is spaced from the junction of the web and said atleast one hollow side flange having the slotted aperture therein to formflange wall portions extending from opposed faces of said intermediateweb, said flange wall portions having spaced respective free edgesdefining the boundaries of said slotted aperture.
 8. The method asclaimed in claim 7 wherein the intermediate web and said hollow sideflanges extending along opposed sides of said web are formed from thesame strip of material.
 9. The method as claimed in claim 7 wherein saidapertured hollow side flange comprises a double walled structure. 10.The method as claimed in claim 7 wherein the intermediate web and atleast one of said hollow side flanges are formed respectively fromseparate strips of material welded together.
 11. The method as claimedin claim 7 wherein said slotted aperture is positioned in a hollow sideflange wall at an angle of between 30° to 180° relative to a planeextending between the longitudinal axis of said hollow side flange andthe junction of said hollow side flange and respective side of saidintermediate web.
 12. The method as claimed in claim 11 wherein both ofsaid opposing hollow side flanges include a slotted aperture extendingbetween respective ends thereof.
 13. The method as claimed in claim 12wherein said slotted aperture has a width such as to substantiallyrestrain relative rotational movement between said apertured hollowflange and a telescopically engaged hollow flange of a like adjacentstructural member.
 14. The method as claimed in claim 11 whereinopposing hollow side flanges have substantially circular cross sections.15. The method as claimed in claim 14 wherein said slotted aperture hasa width such as to permit limited rotational movement of atelescopically engaged hollow flange of a like adjacent structuralmember without flexure of said aperture hollow side flange.
 16. A coldroll formed steel structural member made in accordance with claim
 1. 17.A composite structure comprising two or more edge to edge telescopinglyengaged structural members made in accordance with the process ofclaim
 1. 18. A composite structure as claimed in claim 17 whereinrespective opposite hollow side flanges of a plurality of structuralmembers are telescopically engaged with respective hollow side flangesof adjacent structural members to form a hollow structure.
 19. Acomposite structure as claimed in claim 17 further including structuralmembers having opposed apertured side flanges adapted to telescopicallyengage over a junction between said two or more telescopically edge toedge engaged adjacent structural members.